Back-pressure valve for drilling rigs



1929. E. GRAY ET AL 1,740,770

BACK PRESSURE VALVE FOR DRILLING-Bias] Filed June 2 1926 Patented Dec. 24, 1929 UNITED STATES PATENT OFFICE BACK-PRESSURE VALVE FOR DRILLING RIGS Application filed June 25,

Gray, No. 11,189, filed February 24th, 1925,

there is set out the necessity of a back pressure valve in the drill stem which will revent the surging of the flushing liquid back upwardly into the drill stem against the action of the pumps and thus tend to injure the hose through which the liquid is pumped into the well. As the'valve located in the flushing line is constantly acted upon by the muddy liquid, it must be protected from wear. It is also necessary to cause the valve to seat instantly in case of back pressure in the drilling line.

It is an object of our invention to provide a construction of back pressure valve which will cause the valve to seat immediately when back pressure occurs. It is also an object to provide a peculiar construction of valve whereby the seat upon the valve member is protected against erosion from the flushing liquid which is pumped past the valve in the drilling operation.

In the drawing, we have illustrated the preferred embodiment of the invention. Fig. 1 is a vertical section through a portion of drilling line showing our invention employed therein. Fig. 2 is a similar view partly in elevation showing the valve seated. Fig. 3 is a top plan view of the valve member removed. Fig. 4 is a side view partly in elevation and partly in central vertical section showing the valve member. Fig. 5 is a transverse section of the valve member taken on the line 55 of Fig. 4. Like numerals of reference designate like parts in all the views.

It is contemplated that the back pressure valve may be placed at any desired point in the drilling line. It may be placed adjacent the drill itself or at the upper end of the drillstem above the ground or at any intermediate position. It is preferable, however, to locate the back pressuremember above the ground where it is more easily accessible. In the drawing, the numeral 1 indicates the lower endof the swivel and the member is placed between the swivel and the upper end of the 1926. Serial N0. 118,496.

grief stem 1'. Said back pressure member comprises a specially constructed tool joint, the upper member 2 thereof constituting the pin member and the lower section 3 constituting the box member of the joint.

The pin member 2 is threaded interiorly at its upper end to receive the lower end 4 of the drill stem or other section 1. The lower end of the pin member is threaded at 5 with a coarse thread to fit within the socket formed in the upper end of the box member 3.

We provide a stufling box between the sections 2 and 3 to guard against leakage at this point. This stufiing box is made up of a collar 6 which is threaded interiorly at its lower end to screw over the upper end of the box member 3. Its upper end is extended in wardly to fit about the pin member 2 which is of smaller external diameter than the box member. A shoulder 7 is provided below the upper end of the collar and between this shoulder and the upper end of the box member compressible material 8 is placed which may be compressed by screwing down the collar 6, thus acting to preserve a tight fit at this point.

The inner passage 9 through the box member is larger than the passage A through the grief stem and enlarged intermediate its ends to provide a chamber 10 below the pin member 2 in which the valve 11 may fit. The lower portion of the chamber has a shoulder 12 upon which the valve may normally rest and the lower! end of the pin member 2 is provided with an upwardly tapering seat 13 to receive the valve.

The construction of the valve member is shown best in Figs. 3 to 5 inlusive. It is made up of a solid casting of steel. The lower end of the valve is materially larger than the passage A and is cupped, there being a central cylindrical recess 14 closed at its upper end and connecting with a downwardly flaring opening 15 into which the liquid may be forced. The upper end of the valve member has an upwardly tapered shoulder 16 which is adapted to fit within the tapered seat 13 in the pin member. In order to protect this surface .16 which, forms the valve we .extend the body of the valve member upwardly above the seat, as shown at 17, and the upper end of this projection is tapered at 18in such manner as to deflect the liquid passing downwardly in the drill stem away from the valve surface 16. Below the valve surface are a plurality of radial arms 19, the lower facesof which may rest upon the shoulder 12 in the box member when the valve isopened and the liquid passing downwardly in the drill stem. The lower end of the valve may have a plurality of shorter lugs 20 thereon which fit within the passage 9 and act as a guide to hold the valve centered axially of the water passage.

In the operation of this device, the flushing liquid, which is largely mud, will be pumped downwardly through the dirll stem during the operation of the bit. The liquid used will enter the valve chamber 10 striking upon the upper projection 17 of the valve member, said projection forming a target which acts to deflect the liquid laterally around the valve so that it may pass the valve without hitting the surface 16 with any particular force. We contemplate making the target member of the valve of hardened steel so that it will withstand a considerable amount of erosion .before it will wear appreciably even under the nature of a piston with the full force of the drill stem behind it. The drill stem weighs several tons and the force exerted by the downward drop of the drill is therefore great. The liquid below the drill is, therefore, forced to surge upwardly through the passage in the drill stem to the upper end and, as the liquid is not compressible, the back flow of the liquid must be stopped immediately. This is accomplished through the formation of the cupped lower end of the valve. The liquid passing up against the valve will pass into the "cupped portion and the valve will be driven into its seat immediately before any fluid whatever may pass the valve. In this way the back pressure'of the liquid will be taken off the swivel and the hose at the upper end of the drill stem and no injury whatever will result.

The advantages of this device lie in the particular construction of the valve whereby it is prevented from being easily worn and also in its quick seating properties which efliciently cuts off the back pressureof the water in the drill stem. It has been found possible with this type of back pressure valve to eliminate the usual high-priced and heavy drill hose at the upper end of the line for the flushing fluid due to the fact that it is not subjected to the usual back pressure in spudding. The

valve seats instantly and no heavy pressures are exerted upwardly past the valve; furthermore, the valve is enabled because of its construction to last for long periods of time without replacement.

Having thus described our invention, what we claim as new and desire to protect by Letters Patent is:

1. A back pressure valve for drill stems through which fiushin water is pumped, comprising a valve cham er in said drill stem, a valve member therein, a valve seat above said valve, said valve member having an upwardly tapered surface to fit said seat, and means on said valve and spaced above said surface to deflect the flushing fluid from said valve surface.

2. A back pressure valve for drill stems through which flushing water is pumped, comprising a valve chamber in said drill stem, a valve member therein, a' valve seat above said valve, said valve member having an upwardly tapered surface to fit said seat, and means on said valve above said surface to deflect the flushing fluid from said valve surface, said means comprising an extension above said tapered surface, the upper end of said extension having a tapered deflecting surface.

3. A back pressure valve for use in a drilling string comprising a housing having a water passage therethrough, a valve chamber in said passage, a valve seat at the upper end of said chamber, a valve in said chamber having an annular beveled portion to fit said seat and an upwardly presented target above said beveled portion to deflect the water away from said beveled portion.

4. A back pressure valve for use in a drilling string comprising a housing having a water passage therethrough, said housing having an upper pin member and a lower box member, a'valve chamber in said passage between said members, a valveseat at the upper end of said, chamber, a valve in said chamber having an annular beveled portion to fit said seat and an upwardly presented target spaced above said beveled portion to deflect the water away from said beveled portion.

5. In a back pressure valve of the character described, a housing having a longitudinal fluid passage therein, a valve chamber in said passage, a valve seat in the upper end of said chamber, a valve in said chamber adapted to fit said seat, said valve having its lower side formed with a cupped recess, and means to guide said valve axially of both said chamber and said passage. 7

6. Ina back pressure valve of the character described, a housing having a longitudinal fluid passage therein, a valve chamber in said passage, a valve seat in the upper end of said chamber, a valve in said chamber adapted to fit said seat, said valve having its lower side formed with a cupped recess, and means to guide said valve axially of both said chamber and said passage, comprisingradial lugs on said valve.

7 In a back pressure valve of the character described, a valve body having an annular valve surface shaped to fit a valve seat, and a deflecting target on said-valve above said valve surface, whereby the thrust of the fluid column is normally taken by said target.

8. A back pressure valve for use in a vertically traveling column of abrasive fluid, a housing having a downwardly facing valve seat connecting a fluid passage and a valve chamber, a freely movable valve in said chamber normally held open by gravity, a shoulder in said chamber and projections on said valve adapted to contact with said shoulder and arranged to permit a free flow of fluid, and means carried by said valve to receive the thrust of the fluid column and at least partially deflect said column from said valve surface. I

9. A back pressure valve for use in a vertically traveling column of abrasive fluid, a housing having a downwardly facing valve seat connecting a fluid passage and a valve chamber, a freely movable valve in said chamber normally held open by gravity, a shoulder in said chamber and projections on said valve adapted to contact with said shoulder and arranged to permit a free flow of fluid, and means carried by said valve to receive the thrust of the fluidcolumn and at least partially deflect said column from said valve surface, a portion on said valve below said projection having a centrally disposed cavity therein whereby an upward surge of said fluid column raises said valve. I

10. A back pressure valve normally retained in open position by gravity, a housing for said valve, co-operating contact surfaces on said valve and said housing, and fluid deflecting means to protect the valve surface from the flow of the fluid, said means including a circular fiat surface and a beveled annular surface, said flat surface comprising the major portion of said means.

11. A valve structure comprising a housing, a valve memberin said housing and adapted for free movement in the direction of flow of the fluid, co-operatlng seats on said housing and valve, said member comprising a body portion two series of radially projecting fins on said body, one of said series to limit movement and the other of said series to serve as a guide means, the lower portion of said body being cupped to receive the back thrust of the fluid column to close the valve,

and a fluid deflecting portion to receive-the thrust of the fluid when the valve is in open contact one of said seats and a fluid deflecting area above said surface to take the thrust of the flushing fluid and prevent wear on said valve surface.

In test1mony whereof we hereunto affix our signatures this 14th day of June, A. D.

- ELLSWORTH GRAY.

ROBERT A. MUELLER. 

